Conventionally, manual collection of water samples have been used to assess or measure one or more parameters of interest associated with water quality. Unfortunately, manual collections can be time-consuming and laborious and the sample may be inconsistently obtained at relatively long intervals between collections and/or at different depths in the water column, potentially reducing the value of the information.
In the past, many users have chosen to suspend a probe or sensor from the side of a piling, platform, or buoy to allow readings to be obtained at desired points in time. Commercially available sensors can monitor several parameters with a single integrated probe. These parameters include pH, temperature, turbidity, conductivity, dissolved oxygen, and chlorophyll. Examples of these type of multi-sensor probes include those available from HydroLab Corporation located in Austin, Tex., and other sources such as YSI, Sea-Bird, Wet Labs, Li-Cor, and the like.
One commercial automated water monitoring system, known as the R.U.S.S. Dynamic Profiler™, available from Apprise Technologies, Inc., uses a variable buoyancy technique to raise and lower a multi-sensor probe at selected time intervals and collect water quality data in a water column, allegedly to a depth of about 100 m. The buoyancy-based system can collect the water quality data daily at selected times or upon demand. The collected data can then be forwarded to a remote or central location using various known communication techniques such as cellular, satellite or VHF technology. See Url www.apprisetech.com for additional description of profilers such as that noted above. See also U.S. Pat. Nos. 5,816,874 and 5,606,138 for additional examples of adjustable buoyancy water sampling systems and/or communication transfers between the testing site and a central station; the contents of these patents are hereby incorporated by reference as if recited in full herein.
However, despite the above, conventional automated water quality profiling systems can be relatively expensive, may require undue amounts of power, or may need an undesirable amount of maintenance, and further may not be able to measure the condition of the water at surface level (particularly when monitoring bodies of water having variable water levels). Further, the operation, of known water monitoring systems may unduly shorten the useful life of the probe or sensor used. There remains a need to provide improved low cost alternatives for automated dynamic monitoring of water quality.